R: Return the UTM zone that a WGS84 point belongs to

I'm looking for an R function that might work similarly to this website that will tell you what UTM zone your WGS84 point belongs to.

http://www.rcn.montana.edu/resources/converter.aspx

Answer

Each UTM zone is 6 degrees wide, so you can get the zone number by looking at the longitude:

floor((longitude + 180) / 6) + 1

This assumes that you have longitude within [-180.0, 180.0).